Hey wonder woman, I must say it is possible. My wife and I have been married for 15 years. She has had a long distance boyfriend who is also a very good friend of mine. He and I are both heterosexual. And just 3 weeks ago he moved across the country to live with us!
One thing that is true for us is that its not all about sex. And mostly about friendship, hanging out and enjoying each others company. He and I both love cooking, something my wife hates, so she reaps the benefit of he and I cooking for her on a regular basis.
I think the fact that since he and I get along so well and have other interests in common (in addition to my wife lol) it has made poly work out very well for us. I try to ensure he and her have one on one time and he make sure my wife and I have one on one time as well, but in general we all spend our free time together.
Good luck and hope you find two good men to fulfill you wish! Feel fee to ask any questions.
The characters in another chapter we call life!
T - Wife - Poly
J - Husband Poly